Cmos transistor, semiconductor device including the transistor, and semiconductor module including the device

ABSTRACT

Provided are a CMOS transistor, a semiconductor device having the transistor, and a semiconductor module having the device. The CMOS transistor may include first and second interconnection structures respectively disposed in first and second regions of a semiconductor substrate. The first and second regions of the semiconductor substrate may have different conductivity types. The first and second interconnection structures may be disposed on the semiconductor substrate. The first interconnection structure may have a different stacked structure from the second interconnection structure. The CMOS transistor may be disposed in the semiconductor device. The semiconductor device may be disposed in the semiconductor module.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.12/972,961, filed on Dec. 20, 2010, which claims priority under 35U.S.C. §119 to Korean Patent Application No. 10-2010-0006553 filed inthe Korean Intellectual Property Office on Jan. 25, 2010, the entirecontents of which are hereby incorporated by reference.

BACKGROUND

1. Field

The inventive concept relates to a complementarymetal-oxide-semiconductor (CMOS) transistor, a semiconductor deviceincluding the transistor, and a semiconductor module including thedevice.

2. Description of Related Art

In general, a semiconductor device may include a gate structure formedon a semiconductor substrate. The gate structure controls the flow ofcharge between source and drain regions of a CMOS transistor. The gatestructure may include a gate insulating pattern, a polysilicon (poly-Si)gate and a gate electrode that are sequentially stacked. The poly-Sigate may contain impurity ions. The poly-Si gate may determine the workfunction of the CMOS transistor along with the semiconductor substrate.

When driving the semiconductor device, the poly-Si gate may have aparasitic capacitance due to diffusion of the impurity ions. Theparasitic capacitance of the poly-Si gate may degrade the currentdrivability of the CMOS transistor. In order to prevent generation ofthe parasitic capacitance of the CMOS transistor, the poly-Si gate hasbeen replaced by a diffusion stopping pattern and a metal gate that aresequentially stacked. The metal gate may not develop a parasiticcapacitance during the driving of the semiconductor device.

However, the metal gate may react with the gate electrode and diffuseconstituent atoms of the gate electrode into the diffusion stoppingpattern and/or the gate insulating pattern. In this case, the gateelectrode, depending on semiconductor fabrication process conditions,may cause deviation of a threshold voltage of the CMOS transistor fromits intended magnitude.

The CMOS transistor, which includes the metal gate and the gateelectrode, may be disposed in a semiconductor module and aprocessor-based system. The electrical properties of the semiconductormodule and the process-based system may be degraded by reaction of themetal gate with the gate electrode in the CMOS transistor.

SUMMARY

Embodiments of the inventive concept provide a CMOS transistor includinginterconnection structures, which may prevent diffusion of constituentatoms of a gate electrode.

Embodiments of the inventive concept also provide a semiconductor deviceincluding a CMOS transistor, which may prevent diffusion of constituentatoms of a gate electrode.

Embodiments of the inventive concept also provide a semiconductor moduleincluding the device.

Embodiments of the inventive concept provide a CMOS transistor includingwork-function adjusting materials disposed on a semiconductor substrateand diffusion stopping materials disposed under the work-functionadjusting materials and having different stacked structures, and asemiconductor device and semiconductor module including the CMOStransistor.

According to one aspect, the inventive concept is directed to a CMOStransistor comprising a first interconnection structure and a secondinterconnection structure. The first interconnection structure isdisposed in a first region of a semiconductor substrate and isconfigured to extend from a top surface of the semiconductor substratetoward an upper portion of the semiconductor substrate. The secondinterconnection structure is disposed in a second region of thesemiconductor substrate and is configured to extend from the top surfaceof the semiconductor substrate toward the upper portion of thesemiconductor substrate. Each of the first and second interconnectionstructures includes insulating material, diffusion stopping material,work-function adjusting material, and power applying material that aresequentially stacked, the insulating material and the diffusion stoppingmaterial are disposed in a lower portion of each of the first and secondinterconnection structures, and the diffusion stopping material of thefirst interconnection structure has a different stacked structure fromthe diffusion stopping material of the second interconnection structure.

In one embodiment, the CMOS transistor further includes an insulatinglayer disposed on the semiconductor substrate. The first region of thesemiconductor substrate has a different conductivity type from thesecond region, the first and second interconnection structures have topsurfaces in the upper portion of the semiconductor substrate, theinsulating layer surrounds the first and second interconnectionstructures, and the top surfaces of the first and second interconnectionstructures are at substantially the same level as a top surface of theinsulating layer.

In one embodiment, the CMOS transistor further includes first and secondcapping patterns disposed in the first and second interconnectionstructures, respectively, and an insulating layer configured to surroundthe first and second interconnection structures. The first region of thesemiconductor substrate has a different conductivity type from thesecond region, the first and second capping patterns are disposed inupper portions of the first and second interconnection structures,respectively, and top surfaces of the first and second capping patternsare at substantially the same level as a top surface of the insulatinglayer.

In one embodiment, the CMOS transistor further includes first and secondcapping patterns disposed in the first and second interconnectionstructures, respectively, and an insulating layer configured to surroundthe first and second interconnection structures. The first region of thesemiconductor substrate has a different conductivity type from thesecond region, the first and second interconnection structures protrudefrom a top surface of the insulating layer, extend toward the topsurface of the insulating layer and sequentially dispose parallel to thetop surface of the semiconductor substrate, and the first and secondcapping patterns are disposed in upper portions of the first and secondinterconnection structures, respectively.

In one embodiment, the CMOS transistor further includes an insulatinglayer configured to surround the first and second interconnectionstructures. The first region of the semiconductor substrate has adifferent conductivity type from the second region, the first and secondinterconnection structures have top surfaces in the upper portion of thesemiconductor substrate, each of the top surfaces of the first andsecond interconnection structures is at the same level as or a differentlevel from a top surface of the insulating layer.

According to another aspect, the inventive concept is directed to asemiconductor device including first and second interconnectionstructures. The first interconnection structure includes first andsecond buried patterns sequentially stacked in a first region of asemiconductor substrate to be parallel to a top surface of thesemiconductor substrate, third and fourth buried patterns sequentiallystacked on the second buried pattern to form a concave shape on thesecond buried pattern, and a fifth buried pattern disposed on the fourthburied pattern and surrounded by the third and fourth buried patterns.The second interconnection structure includes first and second stackpatterns sequentially stacked in a second region of the semiconductorsubstrate to be parallel to the top surface of the semiconductorsubstrate, a third stack pattern having the concave shape on the secondstack pattern and configured to extend from a top surface of the secondstack pattern toward an upper portion of the semiconductor substrate,and a fourth stack pattern disposed on the third stack pattern andsurrounded by the third stack pattern. The first buried pattern and thefirst stack pattern include insulating material, the second and thirdburied patterns and the second stack pattern include diffusion stoppingmaterial, the fourth buried pattern and the third stack pattern includework-function adjusting material, and the fifth buried pattern and thefourth stack pattern include power applying material.

In one embodiment, the semiconductor device further includes aninsulating layer disposed on the semiconductor substrate. The insulatinglayer surrounds the first and second interconnection structures, thethird through fifth buried patterns and the third and fourth stackpatterns have substantially the same top surface in the upper portion ofthe semiconductor substrate, and the top surfaces of the third throughfifth buried patterns and the third and fourth stack patterns are atsubstantially the same level as a top surface of the insulating layer.

In one embodiment, the semiconductor device further includes buried andstack capping patterns disposed in the first and second interconnectionstructures, respectively, and an insulating layer disposed on thesemiconductor substrate and configured to surround the first and secondinterconnection structures. The third through fifth buried patterns andthe third and fourth stack patterns have substantially the same topsurface in the upper portion of the semiconductor substrate, the buriedcapping pattern is disposed on the third through fifth buried patterns,the stack capping pattern is disposed on the third and fourth stackpatterns, and top surfaces of the buried and stack capping patterns areat substantially the same level as a top surface of the insulatinglayer.

In one embodiment, the semiconductor device further includes buried andstack capping patterns disposed in the first and second interconnectionstructures, respectively, and an insulating layer disposed on thesemiconductor substrate and configured to surround the first and secondinterconnection structures. Upper portions of the third through fifthburied patterns protrude from a top surface of the insulating layer,extend to the top surface of the insulating layer, and are sequentiallystacked to be parallel to the top surface of the semiconductorsubstrate, upper portions of the third and fourth stack patternsprotrude from the top surface of the insulating layer, extend to the topsurface of the insulating layer, and are sequentially stacked to beparallel to the top surface of the semiconductor substrate, the buriedcapping pattern is disposed on the fifth buried pattern, and the stackcapping pattern is disposed on the fourth stack pattern.

In one embodiment, the semiconductor device further includes aninsulating layer disposed on the semiconductor substrate and configuredto surround the first and second interconnection structures. The thirdthrough fifth buried patterns have top surfaces disposed at the samelevel as or a different level from a top surface of the insulating layerin the upper portions of the semiconductor substrate, and the third andfourth stack patterns have top surfaces disposed at the same level as ora different level from the top surface of the insulating layer in theupper portions of the semiconductor substrate.

In one embodiment, the first region of the semiconductor substrate has adifferent conductivity type from the second region, and the insulatingmaterial includes one selected from the group consisting ofhafnium-based material, lanthanide-based material, zirconium-basedmaterial, Pr₂O₃, Dy₂O₃, Ba_(X)Sr_(Y)TiO_(Z) (BST) material and Pb(Zr,Ti)O₃ (PZT) material.

In one embodiment, a lower portion of the diffusion stopping material ofthe first interconnection structure includes one of binary-based metalnitride and ternary-based metal nitride, and an upper portion of thediffusion stopping material of the first interconnection structureincludes one selected from the group consisting of HfAlN, HfSiN, TaAlN,TaSiN, TiAlN and TiSiN.

In one embodiment, a lower portion of the diffusion stopping material ofthe first interconnection structure includes one of binary-based metalnitride and ternary-based metal nitride, and an upper portion of thediffusion stopping material of the first interconnection structureincludes silicon nitride, silicon carbide or silicide of one selectedfrom the group consisting of hafnium (Hf), molybdenum (Mo), tantalum(Ta), titanium (Ti) and tungsten (W).

In one embodiment, the diffusion stopping material of the secondinterconnection structure includes one of binary-based metal nitride andternary-based metal nitride, or silicide nitride, silicon carbide orsilicide of one selected from the group consisting of Hf, Mo, Ta, Ti andW.

In one embodiment, the work-function adjusting material is carbide,nitride, silicon nitride or silicide of one selected from the groupconsisting of Hf, Mo, Ta, Ti and W, or is one selected from the groupconsisting of platinum (Pt), ruthenium (Ru), iridium oxide (IrO) andruthenium oxide (RuO), and the power applying material includes aluminum(Al) or a combination of Al and Si.

According to another aspect, the inventive concept is directed to asemiconductor module comprising a module substrate and at least onesemiconductor package structure electrically connected to the modulesubstrate and including at least one semiconductor device. The at leastone semiconductor device comprises at least one complementarymetal-oxide-semiconductor (CMOS) transistor disposed in a semiconductorsubstrate, and the at least one CMOS transistor comprises: a firstinterconnection structure disposed in a first region of thesemiconductor substrate and configured to extend from a top surface ofthe semiconductor substrate toward an upper portion thereof; and asecond interconnection structure disposed in a second region of thesemiconductor substrate and configured to extend from the top surface ofthe semiconductor substrate toward the upper portion thereof. Each ofthe first and second interconnection structures includes insulatingmaterial, diffusion stopping material, work-function adjusting material,and power applying material that are sequentially stacked, theinsulating material and the diffusion stopping material are disposed ina lower portion of each of the first and second interconnectionstructures, and the diffusion stopping material of the firstinterconnection structure has a different stacked structure from thediffusion stopping material of the second interconnection structure.

In one embodiment, the semiconductor module further comprises aninsulating layer disposed on the semiconductor substrate. The firstregion of the semiconductor substrate has a different conductivity typefrom the second region, the first and second interconnection structureshave top surfaces in the upper portion of the semiconductor substrate,the insulating layer surrounds the first and second interconnectionstructures, and the top surfaces of the first and second interconnectionstructures are at substantially the same level as a top surface of theinsulating layer.

In one embodiment, the semiconductor module further comprises first andsecond capping patterns disposed in the first and second interconnectionstructures, respectively, and an insulating layer configured to surroundthe first and second interconnection structures. The first region of thesemiconductor substrate has a different conductivity type from thesecond region, the first and second capping patterns are disposed inupper portions of the first and second interconnection structures,respectively, and top surfaces of the first and second capping patternsare at substantially the same level as a top surface of the insulatinglayer.

In one embodiment, the semiconductor module further comprises first andsecond capping patterns disposed in the first and second interconnectionstructures, respectively, and an insulating layer configured to surroundthe first and second interconnection structures. The first region of thesemiconductor substrate has a different conductivity type from thesecond region, the first and second interconnection structure protrudefrom a top surface of the insulating layer, extend toward the topsurface of the insulating layer and sequentially dispose parallel to thetop surface of the semiconductor substrate, and the first and secondcapping patterns are disposed in upper portions of the first and secondinterconnection structures, respectively.

In one embodiment, the semiconductor module further comprises aninsulating layer configured to surround the first and secondinterconnection structures. The first region of the semiconductorsubstrate has a different conductivity type from the second region, thefirst and second interconnection structures have top surfaces in theupper portion of the semiconductor substrate, each of the top surfacesof the first and second interconnection structures is at the same levelas or a different level from a top surface of the insulating layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The inventive concepts will be apparent from the more particulardescription of preferred embodiments thereof, as illustrated in theaccompanying drawings in which like reference characters refer to thesame parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the inventive concepts.

FIG. 1 is a schematic cross-sectional view of a semiconductor samplemanufactured to embody a CMOS transistor according to embodiments of theinventive concept.

FIG. 2 is a schematic cross-sectional view of a MOS capacitormanufactured to embody a complementary MOS transistor according toembodiments of the inventive concept.

FIGS. 3 and 4 are X-ray photoelectron spectroscopy (XPS) graphs of thesemiconductor sample of FIG. 1.

FIGS. 5 and 6 are graphs showing electrical characteristics of a MOScapacitor of FIG. 2.

FIG. 7 is a schematic plan view of a semiconductor device according toembodiments of the inventive concept.

FIG. 8 is a schematic cross-sectional view of a CMOS transistor takenalong lines I-I′ and II-II′ of FIG. 7.

FIGS. 9 through 12 are schematic cross-sectional views taken along linesI-I′ and II-II′ of FIG. 7, illustrating a method of forming a CMOStransistor, according to embodiments of the inventive concept.

FIG. 13 is a schematic cross-sectional view taken along lines I-I′ andII-II′ of FIG. 7, illustrating a method of forming a CMOS transistor,according to embodiments of the inventive concept.

FIG. 14 is a schematic cross-sectional view taken along lines I-I′ andII-II′ of FIG. 7, illustrating a method of forming a CMOS transistor,according to embodiments of the inventive concept.

FIG. 15 is a schematic cross-sectional view taken along lines I-I′ andII-II′ of FIG. 7, illustrating a method of forming a CMOS transistor,according to embodiments of the inventive concept.

FIG. 16 is a schematic cross-sectional view taken along lines I-I′ andII-II′ of FIG. 7, illustrating a method of forming a CMOS transistor,according to embodiments of the inventive concept.

FIG. 17 is a schematic cross-sectional views taken along line III-III′of FIG. 7, illustrating a method of forming a CMOS transistor, accordingto embodiments of the inventive concept.

FIG. 18 is a schematic cross-sectional views taken along line III-III′of FIG. 7, illustrating a method of forming a CMOS transistor, accordingto embodiments of the inventive concept.

FIG. 19 is a schematic cross-sectional views taken along line III-III′of FIG. 7, illustrating a method of forming a CMOS transistor, accordingto embodiments of the inventive concept.

FIG. 20 is a schematic cross-sectional views taken along line III-III′of FIG. 7, illustrating a method of forming a CMOS transistor, accordingto embodiments of the inventive concept.

FIG. 21 is a schematic plan view of a semiconductor module including asemiconductor device of FIG. 7.

FIG. 22 is a schematic plan view of a processor-based system including asemiconductor device of FIG. 7.

DETAILED DESCRIPTION OF EMBODIMENTS

Various embodiments will now be described in detail with reference tothe accompanying drawings in which some embodiments are shown. Theseinventive concepts may, however, be embodied in different forms andshould not be construed as limited to the embodiments set forth herein.Rather, these embodiments are provided so that this description isthorough and complete and fully conveys the inventive concept to thoseskilled in the art. In the drawings, the sizes and relative sizes oflayers and regions may be exaggerated for clarity.

It will be understood that when an element or layer is referred to asbeing “on,” “connected to” or “coupled to” another element or layer, itcan be directly on, connected or coupled to the other element or layer,or intervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on,” “directly connected to”or “directly coupled to” another element or layer, there are nointervening elements or layers present. Like numerals refer to likeelements throughout. As used herein, the term “and/or” includes any andall combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third,etc., may be used herein to describe various elements, components,regions, layers and/or sections, these elements, components, regions,layers and/or sections should not be limited by these terms. These termsare only used to distinguish one element, component, region, layer orsection from another element, component, region, layer or section. Thus,a first element, component, region, layer or section discussed belowcould be termed a second element, component, region, layer or sectionwithout departing from the teachings of the present inventive concept.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element's or feature's relationship to another element(s)or feature(s) as illustrated in the figures. It will be understood thatthe spatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentinventive concept. As used herein, the singular forms “a,” “an” and“the” are intended to include the plural forms as well, unless thecontext clearly indicates otherwise. It will be further understood thatthe terms “comprises” and/or “comprising,” when used in thisspecification, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

Embodiments are described herein with reference to cross-sectionalillustrations that are schematic illustrations of idealized embodiments(and intermediate structures). As such, variations from the shapes ofthe illustrations as a result, for example, of manufacturing techniquesand/or tolerances, are to be expected. Thus, embodiments should not beconstrued as limited to the particular shapes of regions illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, an implanted region illustrated as arectangle will, typically, have rounded or curved features and/or agradient of implant concentration at its edges rather than a binarychange from implanted to non-implanted region. Likewise, a buried regionformed by implantation may result in some implantation in the regionbetween the buried region and the surface through which the implantationtakes place. Thus, the regions illustrated in the figures are schematicin nature and their shapes are not intended to illustrate the actualshape of a region of a device and are not intended to limit the scope ofthe present inventive concept.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this inventive concept belongs. Itwill be further understood that terms, such as those defined in commonlyused dictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Hereinafter, a semiconductor device including a CMOS transistoraccording to embodiments of the inventive concept will be described inmore detail with reference to FIGS. 1 through 8.

FIG. 1 is a schematic cross-sectional view of a semiconductor samplemanufactured to embody a CMOS transistor according to embodiments of theinventive concept.

Referring to FIG. 1, in order to overcome problems of the prior art, asemiconductor sample 20 according to embodiments of the inventiveconcept may include a conductive pattern 16 disposed on a substrate 3.The substrate 3 may include single crystalline silicon (Si) or othermaterial. The substrate 3 may include an impurity diffusion region 6having a selected conductivity type. The impurity diffusion region 6 mayhave the same conductivity type as or a different conductivity type fromthe substrate 3. The impurity diffusion region 6 may include an activeregion 9.

The conductive pattern 16 may be disposed on the active region 9. Theconductive pattern 16 may include titanium nitride. An isolation layer13 may be disposed under the conductive pattern 16. The isolation layer13 may include silicon dioxide (SiO₂) or insulating material having ahigher dielectric constant than the SiO₂. A sacrificial layer 19 may bedisposed on the conductive pattern 16.

In an embodiment, the sacrificial layer 19 may not be disposed on theconductive pattern 16. The sacrificial layer 19 may be disposed on theisolation layer 13 to cover the conductive pattern 16. The sacrificiallayer 19 may be formed of polycrystalline silicon (poly-Si) or SiO₂.When the sacrificial layer 19 is formed of poly-Si, Si atoms of thepoly-Si of the sacrificial layer 19 may diffuse into the conductivepattern 16.

When the sacrificial layer 19 is formed of SiO₂, Si atoms of the SiO₂ ofthe sacrificial layer 19 may diffuse into the conductive pattern 16.Accordingly, two semiconductor samples 20 were prepared according to twotypes of materials in the sacrificial layer 19. For comparison, othertwo semiconductor samples, which were not influenced by the sacrificiallayer 19, were further prepared.

FIG. 2 is a schematic cross-sectional view of a MOS capacitormanufactured to embody a CMOS transistor according to embodiments of theinventive concept.

Referring to FIG. 2, a MOS capacitor 40 according to embodiments of theinventive concept may include the semiconductor substrate 3, theisolation layer 13, and the conductive pattern 16 of FIG. 1. The MOScapacitor 40 may not include the sacrificial layer 19 of FIG. 1. Aplanarization insulating layer 25 may be disposed on the substrate 3.The planarization insulating layer 25 may be disposed on the isolationlayer 13 to cover the conductive pattern 16. The planarizationinsulating layer 25 may include SiO₂.

In this case, the extent of bonding between silicon and oxide in theplanarization insulating layer 25 may be greater than that betweensilicon and oxide in the sacrificial layer 19. Alternatively, theplanarization insulating layer 25 may include insulating material otherthan the sacrificial layer 19. A plug 32 and a first interconnection 34may be disposed adjacent to the conductive pattern 16. The plug 32 maybe in contact with the substrate 3 through the isolation layer 13 andthe planarization insulating layer 25. The first interconnection 34 maybe disposed on the planarization insulating layer 25 and in contact withthe plug 32.

A barrier pattern 36 and a second interconnection 38 may be disposed onthe conductive pattern 16. The barrier pattern 36 may have a concaveshape and be disposed in the planarization insulating layer 25. Thebarrier pattern 36 may be in contact with the conductive pattern 16. Thesecond interconnection 38 may be disposed on the planarizationinsulating layer 25 to fill the concave shape of the barrier pattern 36.The first and second interconnections 34 and 38 may include Al or acombination of Al and Si. In this case, the barrier pattern 36 may beformed of the same material as or different material from the plug 32.

Each of the plug 32 and the barrier pattern 36 may have a stackedstructure of at least two layers. The plug 32 and the barrier pattern 36may completely prevent diffusion of constituent atoms of the first andsecond interconnections 34 and 38. Accordingly, two MOS capacitors 40were prepared according to two types of materials in the sacrificiallayer 19 on the conductive pattern 16 as shown in FIG. 1. Forcomparison, two MOS capacitors, which were not influenced by thesacrificial layer 19 as shown in FIG. 2, were further prepared.

FIGS. 3 and 4 are X-ray photoelectron spectroscopy (XPS) graphs of asemiconductor sample of FIG. 1.

Referring to FIG. 3, first and second semiconductor samples A and Baccording to embodiments of the inventive concept were prepared. Thefirst semiconductor sample A is formed to prevent the influence of thesacrificial layer 19 on the conductive pattern 16 of FIG. 1. The secondsemiconductor sample B is to diffuse silicon (Si) of poly-Si of thesacrificial layer 19 into the conductive pattern 16. Near-surfacecomponents in the conductive patterns 16 of the first and secondsemiconductor samples A and B were analyzed using an X-ray photoelectronspectroscope.

In the two-dimensional graph of FIG. 3, the abscissa denotes bindingenergy (eV), and the ordinate denotes the numbers (Counts/s) ofconstituent atoms extracted from the conductive pattern 16. The bindingenergy may refer to energy required to extract constituent atoms fromconductive patterns. In this case, the X-ray photoelectron spectroscopeconfirmed titanium (Ti) in a near-surface depth of the conductivepattern 16 of the first semiconductor sample A.

The X-ray photoelectron spectroscope confirmed Si in a near-surfacedepth of the conductive pattern 16 of the second semiconductor sample B.A large amount of Si was extracted from the conductive pattern 16 at abinding energy of 533±α eV.

Referring to FIG. 4, third and fourth semiconductor samples C and Daccording to embodiments of the inventive concept were prepared. Thethird semiconductor sample C is formed to prevent the influence of thesacrificial layer 19 of FIG. 1 on the conductive pattern 16 of FIG. 1.The fourth semiconductor sample D is to diffuse Si atoms of silicondioxide of the sacrificial layer 19 into the conductive pattern 16.Near-surface components in the conductive patterns 16 of the third andfourth semiconductor samples C and D were analyzed using an X-rayphotoelectron spectroscope.

As in FIG. 3, in the two-dimensional graph of FIG. 4, the abscissadenotes binding energy (eV), and the ordinate denotes the numbers(Counts/s) of constituent atoms extracted from the conductive pattern16. In this case, the X-ray photoelectron spectroscope confirmed Ti in anear-surface depth of the conductive pattern 16 of the thirdsemiconductor sample C. The X-ray photoelectron spectroscope confirmedSi in a near-surface depth of the conductive pattern 16 of the fourthsemiconductor sample D. A large amount of Si was extracted from theconductive pattern 16 at a binding energy of 102±α eV.

FIGS. 5 and 6 are graphs showing electrical properties of a MOScapacitor of FIG. 2.

Referring to FIG. 5, first and second MOS capacitors E and F accordingto embodiments of the inventive concept were prepared. The first MOScapacitor E is to prevent the influence of the sacrificial layer 19 ofFIG. 1 on the conductive pattern 16. The second MOS capacitor F is todiffuse Si of poly-Si of the sacrificial layer 19 into the conductivepattern 16. A capacitance of each of the first and second MOS capacitorsE and F were measured using a capacitance-voltage (C-V) measurementapparatus.

The C-V measurement apparatus may apply a ground voltage to the firstinterconnection 34 of FIG. 2 and a target voltage to the secondinterconnection 38 of FIG. 2 within a desired range based on the voltageapplied to the first interconnection 34. In the two-dimensional graph ofFIG. 5, the abscissa denotes a voltage Vg applied by the C-V measurementapparatus to the conductive pattern 16, and the ordinate denotes acapacitance. In this case, the second MOS capacitor F showed a smallerflat-band capacitance than the first MOS capacitor E.

The flat-band capacitance is a value obtained when a voltage of 0V isapplied to the second interconnection 38 in each of the first and secondMOS capacitors E and F. The flat-band capacitance may be related to aflat-band voltage in each of the first and second MOS capacitors E andF. The flat-band voltage may be proportional to a threshold voltage ineach of the first and second MOS capacitors E and F. The thresholdvoltage of each of the first and second MOS capacitors E and F may beproportional to a threshold voltage of a CMOS transistor.

The second MOS capacitor F is shown to have a lower threshold voltagethan the first MOS capacitor E. When the Si of the poly-Si of thesacrificial layer 19 diffuses into the conductive pattern 16, the secondMOS capacitor F may provide a basis for stably reducing the thresholdvoltage of the CMOS transistor.

Referring to FIG. 6, third and fourth MOS capacitors G and H wereprepared. The third MOS capacitor G is to prevent the influence of thesacrificial layer 19 of FIG. 1 on the conductive pattern 16. The fourthMOS capacitor H is to diffuse Si of silicon dioxide of the sacrificiallayer 19 into the conductive pattern 16. A capacitance of each of thethird and fourth MOS capacitors G and H was measured using a C-Vmeasurement apparatus.

The C-V measurement apparatus may apply the same voltages as FIG. 5 tothe first and second interconnections 34 and 38 of FIG. 1. As in FIG. 5,in the two-dimensional graph of FIG. 6, the abscissa denotes a voltageVg applied by the C-V measurement apparatus to the conductive pattern16, and the ordinate denotes a capacitance. In this case, the fourth MOScapacitor H showed a greater flat-band capacitance than the third MOScapacitor G. The fourth MOS capacitor H may have a higher thresholdvoltage than the third MOS capacitor G.

When the Si of the silicon dioxide of the sacrificial layer 19 diffusesinto the conductive pattern 16, the fourth MOS capacitor H may provide abasis for stably increasing the threshold voltage of the CMOStransistor.

Due to the C-V characteristics of the fourth MOS capacitor, the immunityof a conventional CMOS transistor to a drop in a threshold voltage maybe increased. Also, the fourth MOS capacitor provides an approach toimproving electrical characteristics of a CMOS transistor compared withthe prior art, together with the second MOS capacitor. To do this,embodiments of the inventive concept may provide a ternary-based metalnitride interposed between a diffusion stopping pattern and a metal gateof the prior art.

FIG. 7 is a schematic plan view of a semiconductor device according toembodiments of the inventive concept.

Referring to FIG. 7, a semiconductor device 310 according to embodimentsof the inventive concept may include a first region R1 and a secondregion R2. The first and second regions R1 and R2 may have thirdinterconnection structures 294 or 298, which are electrically insulatedfrom one another. The first region R1 may have a p-type impuritydiffusion region 54, which may have a selected third interconnectionstructure 294 or 298. A first interconnection structure 153, 156, or 159and first and second active regions 62 and 64 may be disposed in thep-type impurity diffusion region 54 to overlap the selected thirdinterconnection structure 294 or 298.

The first interconnection structure 153, 156, or 159 may be disposedacross the first active region 62. The first interconnection structure153, 156, or 159 and the first and second active regions 62 and 64 maybe electrically connected to the selected third interconnectionstructure 294 or 298 through connection hole 245. In this case, theselected third interconnection structure 294 or 298 may constitute ann-type MOS (NMOS) transistor along with the p-type impurity diffusionregion 54 and the first and second active regions 62 and 64.

The second region R2 may have an n-type impurity diffusion region 58.The n-type impurity diffusion region 58 may have the remaining thirdinterconnection structures 294 or 298. A second interconnectionstructure 223, 226, or 229 and third and fourth active regions 66 and 68may be disposed in an n-type impurity diffusion region 58. The secondinterconnection structure 223, 226, or 229 may be disposed across thethird active region 66. The second interconnection structure 223, 226,or 229 and the third and fourth active regions 66 and 68 may beelectrically connected to the remaining third interconnection structures294 or 298 through the connection holes 245.

In this case, the remaining third interconnection structures 294 or 298may constitute a p-type MOS (PMOS) transistor along with the n-typeimpurity diffusion region 58 and the third and fourth active regions 66and 68. As a result, the PMOS transistor and the NMOS transistor mayconstitute a CMOS transistor 300 in the semiconductor device 310.

FIG. 8 is a cross-sectional view of a CMOS transistor taken along linesI-I′ and II-II′ of FIG. 7.

Referring to FIG. 8, a CMOS transistor 300 according to embodiments ofthe inventive concept may include first and second interconnectionstructures 153 and 223 on a semiconductor substrate 50. Thesemiconductor substrate 50 may include the same material as or differentmaterial from the substrate 3 of FIG. 1. The first interconnectionstructure 153 may be disposed on a first active region 62 of a p-typeimpurity region 54 of the semiconductor substrate 50. The firstinterconnection structure 153 may extend from a top surface of thesemiconductor substrate 50 toward an upper portion thereof. The firstinterconnection structure 153 may include first through fifth buriedpatterns 106, 116, 126, 136, and 146.

The first and second buried patterns 106 and 116 may be sequentiallydisposed on the semiconductor substrate 50 to be parallel to the topsurface of the semiconductor substrate 50. The third and fourth buriedpatterns 126 and 136 may be sequentially stacked on the second buriedpattern 116. The third and fourth buried patterns 126 and 136 may form aconcave shape on the second buried pattern 116. Each of the third andfourth buried patterns 126 and 136 may have an opening toward the upperportion of the semiconductor substrate 50. The fifth buried pattern 146may be disposed on the fourth buried pattern 136 and surrounded by thethird and fourth buried patterns 126 and 136.

In this case, the first buried pattern 106 and/or the second buriedpattern 116 may also be disposed along sidewalls of the third buriedpattern 126. The first buried pattern 106 may include insulatingmaterial. The second and third buried patterns 116 and 126 may includediffusion stopping material. The third buried pattern 126 may includeternary-based metal nitride as the resultant material of FIGS. 1 through6. The fourth buried pattern 136 may include work-function adjustingmaterial.

The fourth buried pattern 136 may be a metal gate. The fifth buriedpattern 146 may include power applying material. The fifth buriedpattern 146 may be a gate electrode. First source and drain regions (notshown) may be disposed in the semiconductor substrate 50 adjacent to thefirst through fifth buried patterns 106, 116, 126, 136, and 146.

The second interconnection structure 223 may be disposed on a thirdactive region 66 of an n-type impurity region 58 of the semiconductorsubstrate 50. The second interconnection structure 223 may extend from atop surface of the semiconductor substrate 50 toward an upper portionthereof. The second interconnection structure 223 may include firstthrough fourth stack patterns 164, 174, 184, and 194. The first andsecond stack patterns 164 and 174 may be sequentially disposed on thesemiconductor substrate 50 to be parallel to the top surface of thesemiconductor substrate 50. The third stack pattern 184 may extend froma top surface of the second stack pattern 174 toward the upper portionof the semiconductor substrate 50. The third stack pattern 184 may forma concave shape on the second stack pattern 174.

The third stack pattern 184 may have an opening toward the upper portionof the semiconductor substrate 50. The fourth stack pattern 194 may bedisposed on the third stack pattern 184 and may be surrounded by thethird stack pattern 184. The third and fourth stack patterns 184 and 194may have the substantially same top surface as the third through fifthburied patterns 126, 136, and 146 in the upper portion of thesemiconductor substrate 50.

In this case, the first stack pattern 164 and/or the second stackpattern 174 may be also disposed along sidewalls of the third stackpattern 184. The first stack pattern 164 may include the same insulatingmaterial as or different insulating material from the first buriedpattern 106. The second stack pattern 174 may include the same diffusionstopping material as or different diffusion stopping material from thesecond buried pattern 116. The third stack pattern 184 may include thesame work-function adjusting material as or different work-functionadjusting material from the fourth buried pattern 136. The fourth stackpattern 194 may include the same power applying material as or differentpower applying material from the fifth buried pattern 146.

Second source and drain regions (not shown) may be disposed in thesemiconductor substrate 50 adjacent to the first through fourth stackpatterns 164, 174, 184, and 194. A first insulating layer 81 may bedisposed on the semiconductor substrate 50. The first insulating layer81 may surround the first through fifth buried patterns 106, 116, 126,136, and 146 and the first through fourth stack patterns 164, 174, 184,and 194. A top surface of the first insulating layer 81 may be at thesubstantially same level as top surfaces of the third through fifthburied patterns 126, 136, and 146 and the third and fourth stackpatterns 184 and 194. A second insulating layer 240 may be disposed onthe first insulating layer 81, the third through fifth buried patterns126, 136, and 146, and the third and fourth stack patterns 184 and 194.

Embodiment 1

FIGS. 9 through 12 are schematic cross-sectional views taken along linesI-I′ and II-IP of FIG. 7, illustrating a method of forming a CMOStransistor, according to embodiments of the inventive concept.

Referring to FIG. 9, according to embodiments of the inventive concept,a semiconductor substrate 50 may be prepared. The semiconductorsubstrate 50 may include the same material as or different material fromthe substrate 3 of FIG. 1. The semiconductor substrate 50 may include p-and n-type impurity diffusion regions 54 and 58. The p- and n-typeimpurity diffusion regions 54 and 58 may include first and third activeregions 62 and 66, respectively. The first active region 62 may includefirst source and drain regions (not shown). The first source and drainregions may have a different conductivity type from the p-type impuritydiffusion regions 54.

The third active region 66 may include second source and drain regions(not shown). The second source and drain regions may have a differentconductivity type from the n-type impurity diffusion regions 58. A firstinsulating layer 81 may be formed on the semiconductor substrate 50 tocover the first and third active regions 62 and 66. The first insulatinglayer 81 may include insulating material having a different etch ratefrom the semiconductor substrate 50. First and second trenches 83 and 85may be formed in the first insulating layer 81. The first trench 83 mayexpose the first active region 62 between the first source and drainregions.

The second trench 85 may expose the third active region 66 between thesecond source and drain regions. A protection layer 87 may be formed inthe first and second trenches 83 and 85. The protection layer 87 may bedisposed in lower portions of the first and second trenches 83 and 85 tocover the semiconductor substrate 50. The protection layer 87 mayinclude material having the same etch rate as or a different etch ratefrom the semiconductor substrate 50 and/or the first insulating layer81. Threshold-voltage adjusting impurity ions may or may not beimplanted into the semiconductor substrate 50 within the first andsecond trenches 83 and 85 using the first insulating layer 81 and theprotection layer 87 as a buffer layer.

The threshold-voltage adjusting impurity ions in the first trench 83 mayhave the same conductivity type as or a different conductivity type fromthe threshold-voltage adjusting impurity ions in the second trench 85.Fill patterns 89 may be formed in the first and second trenches 83 and85. The fill patterns 89 may be disposed on the protection layer 87 tofill the first and second trenches 83 and 85. The fill patterns 89 mayinclude material having the same etch rate as or a different etch ratefrom the protection layer 87. A first mask pattern 95 may be formed onthe first insulating layer 81 in the third active region 66. The firstmask pattern 95 may cover the entire n-type impurity diffusion region 58of FIG. 7.

The first mask pattern 95 may include material having the same etch rateas or a different etch rate from the first insulating layer 81 and thefill patterns 89.

Referring to FIG. 10, according to embodiments of the inventive concept,the fill pattern 89 may be removed from the first trench 83 using thefirst mask pattern 95 of FIG. 9 as an etch mask and using the firstinsulating layer 81 and the protection layer 87 as an etch buffer layer.The protection layer 87 may be removed from the first active region 62using the first mask pattern 95 as an etch mask and using thesemiconductor substrate 50 and the first insulating layer 81 as an etchbuffer layer. After removing the protection layer 87, the first maskpattern 95 may be removed from the third active region 66.

Thereafter, first and second buried patterns 106 and 116 and thirdthrough fifth buried layers 120, 130, and 140 may be sequentially formedon the semiconductor substrate 50 to fill the first trench 83. The firstand second buried patterns 106 and 116 may be formed in a lower portionof the first trench 83 and cover the first insulating layer 81 and thefill pattern 89. The third and fourth buried layers 120 and 130 mayconformally cover the first trench 83. The fifth buried layer 140 may bedisposed on the fourth buried layer 130 to fill the first trench 83.

The first buried pattern 106 may include insulating material. Theinsulating material may include hafnium-based material andlanthanide-based material. The hafnium-based material may include HfAlO,HfLaO, HfO₂, HfON, HfSiO, or HfSiON. The lanthanide-based material mayinclude La₂O₃ or LaAlO₃. The insulating material may also includezirconium-based material, dysprosium oxide (Dy₂O₃), praseodymium oxide(Pr₂O₃), Ba_(X)Sr_(Y)TiO_(Z) (BST) material, or Pb(Zr, Ti)O₃ (PZT)material.

The zirconium-based material may include ZrO₂, ZrSiO, or ZrSiON. Thefirst buried pattern 106 may be formed using a chemical vapor deposition(CVD) process, a physical vapor deposition (PVD) process, an atomiclayer deposition (ALD) process, or a combination thereof. The secondburied pattern 116 may include first diffusion stopping material. Thefirst diffusion stopping material may include one of binary-based metalnitride and ternary-based metal nitride.

The binary-based metal nitride may include HfN, TaN, TiN, or WN. Theternary-based metal nitride may include HfAlN, TaAlN, or TiAlN. Thesecond buried pattern 116 may be formed using a CVD process, a PVDprocess, an ALD process, or a combination thereof. The third buriedlayer 120 may include second diffusion stopping material. The seconddiffusion stopping material may include HfAlN, HfSiN, TaAlN, TaSiN,TiAlN, or TiSiN.

The formation of the second diffusion stopping material may includeperforming a plasma-enhanced CVD (PECVD) process using a targetincluding a metal-silicon-nitride or a metal-aluminum-nitride, orimplanting Si ions into a binary-based metal nitride. Themetal-aluminum-nitride may prevent diffusion of constituent atoms of thefifth buried layer 140. Alternatively, the formation of the seconddiffusion stopping material may include depositing silicon and/orsilicon nitride on binary-based metal nitride using an ALD process andremoving the silicon and/or the silicon nitride from the binary-basedmetal nitride. Alternatively, the formation of the second diffusionstopping material may include depositing silicon oxide on binary-basedmetal nitride using a CVD process and removing the silicon oxide fromthe binary-based metal nitride.

The second diffusion stopping material may include silicon nitride,silicon carbide, or silicide of one selected from the group consistingof hafnium (Hf), molybdenum (Mo), tantalum (Ta), titanium (Ti), andtungsten (W). The fourth buried layer 130 may include work-functionadjusting material. The work-function adjusting material may includecarbide, nitride, silicon nitride, or silicide of one selected from thegroup consisting of Hf, Mo, Ta, Ti, and W.

The work-function adjusting material may also include platinum (Pt),ruthenium (Ru), iridium oxide (40), and ruthenium oxide (RuO). Thefourth buried layer 130 may be formed using a CVD process, a PVDprocess, an ALD process, or a combination thereof. The fifth buriedlayer 140 may include power applying material. The power applyingmaterial may include Al or a combination of Al and Si. The fifth buriedlayer 140 may be formed using a CVD process, a PVD process, an ALDprocess, or a combination thereof.

In this case, the second buried pattern 116 and the third buried layer120 may completely prevent diffusion of constituent atoms of the fifthburied layer 140 from the fourth buried layer 130 to the first buriedpattern 106.

Referring to FIG. 11, according to embodiments of the inventive concept,an etchback process and/or a chemical mechanical polishing (CMP) processmay be performed on the third through fifth buried layers 120, 130, and140 of FIG. 10. That is, the third through fifth buried layers 120, 130,and 140 may be etched using the etchback process and/or the CMP processto form third through fifth preliminary buried patterns 123, 133, and143. The third through fifth preliminary buried patterns 123, 133, and143 may be formed to expose the first insulating layer 81 and fill thefirst trench 83 in the first active region 62.

Furthermore, the third through fifth preliminary buried patterns 123,133, and 143 may expose the first insulating layer 81 and the fillpattern 89 in the third active region 66. After forming the thirdthrough fifth preliminary buried patterns 123, 133, and 143, a secondmask pattern (not shown) may be formed on the first insulating layer 81to cover the third through fifth preliminary buried patterns 123, 133,and 143. The second mask pattern may cover the entire p-type impuritydiffusion region 54 of FIG. 7.

The second mask pattern may include material having the same etch rateas or a different etch rate from the first insulating layer 81 and thethird through fifth preliminary buried patterns 123, 133, and 143. Thefill pattern 89 may be removed from the second trench 85 using thesecond mask pattern of the first active region 62 and the firstinsulating layer 81 of the third active region 66 as an etch mask and anetch buffer layer, respectively. Subsequently, the protection layer 87may be removed using the second mask pattern as an etch mask and usingthe semiconductor substrate 50 and the first insulating layer 81 as anetch buffer layer.

After removing the protection layer 87 of the third active region 66,the second mask pattern may be continuously removed from the firstactive region 62. First and second stack patterns 164 and 174 and thirdand fourth stack layers 180 and 190 may be sequentially formed on thesemiconductor substrate 50 to fill the second trench 85. The first andsecond stack patterns 164 and 174 may be formed in a lower portion ofthe second trench 85. The first stack pattern 164 may include insulatingmaterial. The first stack pattern 164 may include the same material asor different material from the first buried pattern 106. The secondstack pattern 174 may include diffusion stopping material.

The second stack pattern 174 may include the same material as ordifferent material from the second buried pattern 116. The second stackpattern 174 may also include the same material as the third preliminaryburied pattern 123. The third stack layer 180 may include work-functionadjusting material. The third stack layer 180 may include the samematerial as or different material from the fourth preliminary buriedpattern 133. The fourth stack layer 190 may include power applyingmaterial. The fourth stack layer 190 may include the same material as ordifferent material from the fifth preliminary buried pattern 143.

In this case, the third buried layer 120 of FIG. 10 may also be formedbetween the second stack pattern 174 and the third stack layer 180.

Referring to FIG. 12, according to embodiments of the inventive concept,an etchback process and/or a CMP process may be performed on the thirdthrough fifth preliminary buried patterns 123, 133, and 143 of FIG. 11,and third and fourth stack layers 180 and 190. The third and fourthstack layers 180 and 190 may be etched using the etchback process and/orthe CMP process to form the third and fourth stack patterns 184 and 194.

The third and fourth stack patterns 184 and 194 may be formed to exposethe first insulating layer 81 of the third active region 66. The firstthrough fourth stack patterns 164, 174, 184, and 194 may be formed tosufficiently fill the second trench 85. Furthermore, the third throughfifth preliminary buried patterns 123, 133, and 143 may be etched usingthe etchback process and/or the CMP process to form the third throughfifth buried patterns 126, 136, and 146. The third through fifth buriedpatterns 126, 136, 146 may be formed to expose the first insulatinglayer 81 of the first active region 62.

The first through fifth buried patterns 106, 116, 126, 136, and 146 maybe formed to sufficiently fill the first trench 83. The third throughfifth buried patterns 126, 136, and 146 may have substantially the sametop surface as the third and fourth stack patterns 184 and 194 in theupper portion of the semiconductor substrate 50. The third through fifthburied patterns 126, 136, and 146 and the third and fourth stackpatterns 184 and 194 may have substantially the same top surface as thefirst insulating layer 81. The first through fifth buried patterns 106,116, 126, 136, and 146 may constitute a first interconnection structure153. The first through fourth stack patterns 164, 174, 184, and 194 mayconstitute a second interconnection structure 223.

Thereafter, a second insulating layer 240 may be formed on the firstinsulating layer 81 and the first and second interconnection structures153 and 223. The second insulating layer 240 may include material havingthe same etch rate as or a different etch rate from the first insulatinglayer 81. The second insulating layer 240 may have the same etch rate asor a different etch rate from the third through fifth buried patterns126, 136, and 146 and/or the third and fourth stack patterns 184 and194.

As such, the first and second interconnection structures 153 and 223 mayconstitute a CMOS transistor 300 along with the semiconductor substrate50. According to modified embodiments of the inventive concept, a methodof forming a CMOS transistor 300 may include firstly forming first andsecond stack patterns 164 and 174 and third and fourth stack layers 180and 190 in a second trench 85 of a third active region 66. Next, themethod of forming the CMOS transistor 300 may further include formingfirst and second buried patterns 106 and 116 and third through fifthburied layers 120, 130, and 140 in a first trench 83 of a first activeregion 62.

Embodiment 2

FIG. 13 is a schematic cross-sectional view taken along lines I-I′ andII-II′ of FIG. 7, illustrating a method of forming a CMOS transistor,according to embodiments of the inventive concept. In FIG. 13, the samereference numerals are used to denote the same elements as in FIGS. 9through 12.

Referring to FIG. 13, according to embodiments of the inventive concept,an etchback process may be performed on the third through fifthpreliminary buried patterns 123, 133, and 143 and the third and fourthstack layers 180 and 190 of FIG. 11. The third and fourth stack layers180 and 190 may be etched using the etchback process, thereby formingthird and fourth stack patterns 184 and 194.

The third and fourth stack patterns 184 and 194 may be formed under atop surface of a first insulating layer 81 of a third active region 66to expose the first insulating layer 81. The first through fourth stackpatterns 164, 174, 184, and 194 may be formed to partially fill thesecond trench 85. Also, the third through fifth preliminary buriedpatterns 123, 133, and 143 may be etched using the etchback process,thereby forming third through fifth buried patterns 126, 136, and 146.The third through fifth buried patterns 126, 136, and 146 may be formedunder a top surface of the first insulating layer 81 of the first activeregion 62 to expose the first insulating layer 81.

The first through fifth buried patterns 106, 116, 126, 136, and 146 maybe formed to partially fill the first trench 83. The third through fifthburied patterns 126, 136, and 146 may or may not have the substantiallysame top surface as the third and fourth stack patterns 184 and 194.First buried and stack capping patterns 214 may be formed on the firstthrough fifth buried patterns 106, 116, 126, 136, and 146 and the firstthrough fourth stack patterns 164, 174, 184, and 194. The first buriedand stack capping patterns 214 may include material having the same etchrate as or a different etch rate from the first insulating layer 81.

The first buried and stack capping patterns 214 may be formed to fillupper portions of the first and second trenches 83 and 85, respectively.Top surfaces of the first buried and stack capping patterns 214 may ormay not be disposed at substantially the same level as the top surfaceof the first insulating layer 81. The first through fifth buriedpatterns 106, 116, 126, 136, and 146 may constitute a firstinterconnection structure 156 along with the first buried cappingpattern 214 in a first active region 62. The first through fourth stackpatterns 164, 174, 184, and 194 may constitute a second interconnectionstructure 226 along with the first buried and stack capping pattern 214in a third active region 66. A second insulating layer 240 may be formedon the first and second interconnection structures 153 and 226 to coverthe first insulating layer 81. As such, the first and secondinterconnection structures 156 and 226 may be included in a CMOStransistor 300 along with a semiconductor substrate 50.

According to modified embodiments of the inventive concept, a method offorming a CMOS transistor 300 may include firstly forming first andsecond stack patterns 164 and 174 and third and fourth stack layers 180and 190 in a second trench 85 of the third active region 66. Next, themethod of forming the CMOS transistor 300 may further include formingfirst and second buried patterns 106 and 116 and third through fifthburied layers 120, 130, and 140 in a first trench 83 of the first activeregion 62.

Embodiment 3

FIG. 14 is a schematic cross-sectional view taken along lines I-I′ andII-II′ of FIG. 7, illustrating a method of forming a CMOS transistor,according to embodiments of the inventive concept. In FIG. 14, the samereference numerals are used to denote the same elements as in FIGS. 12and 13.

Referring to FIG. 14, according to embodiments of the inventive concept,first through fifth buried patterns 106, 116, 126, 136, and 146 may beformed in the first trench 83 of a first active region 62 as shown inFIG. 12. According to the embodiments of the inventive concept, firstthrough fourth stack patterns 164, 174, 184, and 194 may be formed inthe second trench 85 of a third active region 66 as shown in FIG. 12. Athird mask (not shown) may be formed on a first insulating layer 81 ofthe first active region 62 to cover the first through fifth buriedpatterns 106, 116, 126, 136, and 146.

The third mask pattern may cover the entire p-type impurity diffusionregion 54 of FIG. 7. The third mask pattern may include material havingthe same etch rate as or a different etch rate from the first insulatinglayer 81. An etchback process may be performed on the third and fourthstack patterns 184 and 194 using the third mask pattern of the firstactive region 62 and the first insulating layer 81 of the third activeregion 66 as an etch mask and an etch buffer layer, respectively. Theetchback process may be performed to locate the third and fourth stackpatterns 184 and 194 under a top surface of the first insulating layer81.

The first through fourth stack patterns 164, 174, 184, and 194 may beformed to partially fill the second trench 85. After performing theetchback process, the third mask pattern may be removed from the firstactive region 62. Thereafter, the first stack capping pattern 214 ofFIG. 13 may be formed to fill an upper portion of the second trench 85.Thus, the first through fifth buried patterns 106, 116, 126, 136, and146 may constitute the first interconnection structure 153 of FIG. 12 onthe first active region 62. The first through fourth stack patterns 164,174, 184, and 194 may constitute the second interconnection structure226 of FIG. 13 along with the first stack capping pattern 214.

A second insulating layer 240 may be formed on the first and secondinterconnection structures 153 and 226 to cover the first insulatinglayer 81. As such, the first and second interconnection structures 153and 226 may be included in a CMOS transistor 300 along with asemiconductor substrate 50. According to modified embodiments of theinventive concept, a method of forming the CMOS transistor 300 mayinclude firstly forming first and second stack patterns 164 and 174 andthird and fourth stack layers 180 and 190 in the second trench 85 of athird active region 66.

Next, the method of forming the CMOS transistor 300 may further includeforming first and second buried patterns 106 and 116 and third throughfifth buried layer 120, 130, and 140 in a first trench 83 of a firstactive region 62. Also, the first buried capping pattern 214 of FIG. 13may be formed only on third through fifth buried patterns 126, 136, and146 instead of the first stack capping pattern 214 of FIG. 14. In thiscase, first through fifth buried patterns 106, 116, 126, 136, and 146may constitute the first interconnection structure 156 of FIG. 13 alongwith the first buried capping pattern 214.

Embodiment 4

FIG. 15 is a schematic cross-sectional view taken along lines I-I′ andII-II′ of FIG. 7, illustrating a method of forming a CMOS transistor,according to embodiments of the inventive concept. In FIG. 15, the samereference numerals are used to denote the same elements as in FIGS. 10through 12.

Referring to FIG. 15, according to embodiments of the inventive concept,a second buried capping layer (not shown) may be formed on the fifthburied layer 140 of FIG. 10. The second buried capping layer may includematerial having the same etch rate as or a different etch rate from thefifth buried layer 140. Primary semiconductor photolithography andetching processes may be performed on the third through fifth buriedlayers 120, 130, and 140 and the second buried capping layer. Thus, aphotoresist pattern may be formed on the second buried capping layerusing the primary semiconductor photolithography process.

The photoresist pattern may be aligned with the first trench 83 toexpose the second buried capping layer. The primary semiconductoretching process may be performed on the third through fifth buriedlayers 120, 130, and 140 and the second buried capping layer using thephotoresist pattern and a first insulating layer 81 as an etch mask andan etch buffer layer, respectively. The third through fifth buriedlayers 120, 130, and 140 and the second buried capping layer may beetched using the primary semiconductor etching process, thereby formingthird through fifth buried patterns 129, 139, and 149 and a secondburied capping pattern 216.

Upper portions of the third and fourth buried patterns 129 and 139 mayprotrude from a top surface of the first insulating layer 81. To thisend, the upper portions of the third and fourth buried patterns 129 and139 may extend to the top surface of the insulating layer 81, and may besequentially formed parallel to a top surface of the semiconductorsubstrate 50. The fifth buried pattern 149 may be formed on the fourthburied pattern 139 to fill the first trench 83.

The first through fifth buried patterns 106, 116, 129, 139, and 149 andthe second buried capping pattern 216 may constitute a firstinterconnection structure 159 in a first active region 62. The firstinterconnection structure 159 may be formed to expose the firstinsulating layer 81, and a fill pattern 89 in the third active region 66of FIG. 10. After forming the first interconnection structure 159, thephotoresist pattern may be removed from the semiconductor substrate 50.A fourth mask pattern (not shown) may be formed on the p-type impuritydiffusion region 54 of FIG. 7 to cover the first interconnectionstructure 159.

The fourth mask pattern may include material having the same etch rateas or a different etch rate from the first insulating layer 81.Subsequently, as described with reference to FIG. 11, a protection layer87 and the fill pattern 89 of FIG. 10 may be removed from the thirdactive region 66 using the fourth mask pattern as an etch mask. Thefirst and second stack patterns 164 and 174 and the third and fourthstack layers 180 and 190 of FIG. 11 may be formed in a second trench 85of the third active region 66. A second stack capping layer (not shown)may be formed on the fourth stack layer 190.

The second stack capping layer may include material having the same etchrate as or a different etch rate from the fourth stack layer 190.Secondary semiconductor photolithography and etching processes may beperformed on the third and fourth stack layers 180 and 190 and thesecond stack capping layer. Thus, a photoresist pattern may be formed onthe second stack capping layer using the secondary semiconductorphotolithography process. The photoresist pattern may expose the secondstack capping layer and be aligned with the second trench 85. Thesecondary semiconductor etching process may be performed on the thirdand fourth stack layers 180 and 190 and the second stack capping layerusing the photoresist pattern and the first insulating layer 81 as anetch mask and an etch buffer layer, respectively.

The third and fourth stack layers 180 and 190 and the second stackcapping layer may be etched using the secondary semiconductor etchingprocess, thereby forming third and fourth stack patterns 188 and 198 anda stack capping pattern 218. An upper portion of the third stack pattern188 may protrude from the top surface of the first insulating layer 81.To this end, the upper portion of the third stack pattern 188 may extendto the top surface of the first insulating layer 81 and may besequentially formed parallel to the top surface of the semiconductorsubstrate 50.

The fourth stack pattern 198 may be formed on the third stack pattern188 to fill the second trench 85. The first through fourth stackpatterns 164, 174, 188, and 198 and the second stack capping pattern 218may constitute a second interconnection structure 229 in the thirdactive region 66. After forming the second interconnection structure229, the photoresist pattern and the fourth mask pattern may be removedfrom the semiconductor substrate 50. Spacers 235 may be formed onsidewalls of the first and second interconnection structures 159 and229.

The spacers 235 may include material having the same etch rate as or adifferent etch rate from the second buried capping pattern 216 and/orthe second stack capping pattern 218. A second insulating layer 240 maybe formed on the semiconductor substrate 50 to cover the first andsecond interconnection structures 159 and 229 and the spacers 235. Assuch, the first and second interconnection structures 159 and 229 may beincluded in a CMOS transistor 300 along with the semiconductor substrate50.

According to modified embodiments of the inventive concept, a method offorming a CMOS transistor 300 may include firstly forming first throughfourth stack patterns 164, 174, 188, and 198 and the second stackcapping pattern 218 in the second trench 85 of the third active region66. Next, the method of forming the CMOS transistor 300 may furtherinclude forming first through fifth buried patterns 106, 116, 129, 139,and 149 and the second buried capping pattern 216 in the first trench 83of the first active region 62.

Embodiment 5

FIG. 16 is a schematic cross-sectional view taken along lines I-I′ andII-II′ of FIG. 7, illustrating a method of forming a CMOS transistor,according to embodiments of the inventive concept. In FIG. 16, the samereference numerals are used to denote the same elements as in FIGS. 14and 15.

Referring to FIG. 16, according to embodiments of the inventive concept,the first interconnection structure 159 of FIG. 15 may be formed in afirst trench 83 of a first active region 62. After forming the firstinterconnection structure 159, the fourth mask pattern of FIG. 15 may beformed to cover the first interconnection structure 159. Before formingthe fourth mask pattern, spacers 235 may be formed on sidewalls of thefirst interconnection structure 159. Subsequently, as described withreference to FIG. 11, a protection layer 87 and a fill pattern 89 ofFIG. 1 may be removed from a third active region 66 using the fourthmask pattern as an etch mask.

The first and second stack patterns 164 and 174 and the third and fourthstack layers 180 and 190 of FIG. 11 may be formed in a second trench 85of the third active region 66. By using the fourth mask pattern and thefirst insulating layer 81 as an etch mask and an etch buffer layer,respectively, an etchback process may be performed on the third andfourth stack layers 180 and 190. The third and fourth stack layers 180and 190 may be etched using the etchback process, thereby forming thirdand fourth stack patterns 184 and 194.

The third and fourth stack patterns 184 and 194 may be formed under atop surface of the first insulating layer 81 to partially fill thesecond trench 85. The first stack capping pattern 214 of FIG. 14 may beformed on the third and fourth stack patterns 184 and 194. The firststack capping pattern 214 may constitute the second interconnectionstructure 226 of FIG. 14 along with the first through fourth stackpatterns 164, 174, 184, and 194. After forming the first stack cappingpattern 214, the fourth mask pattern may be removed from thesemiconductor substrate 50.

Subsequently, a second insulating layer 240 may be formed to cover thefirst and second interconnection structures 159 and 226 and the spacers235. As such, the first and second interconnection structures 159 and226 may be included in a CMOS transistor 300 along with thesemiconductor substrate 50. According to modified embodiments of theinventive concept, a method of forming a CMOS transistor 300 may includeforming the first interconnection structure 1 of FIG. 13 in the firsttrench 83 of the first active region 62 and forming the secondinterconnection structure of FIG. 15 in the second trench 85 of thethird active region 66.

Embodiment 6

FIG. 17 is a schematic cross-sectional views taken along line III-III′of FIG. 7, illustrating a method of forming a CMOS transistor, accordingto embodiments of the inventive concept.

Referring to FIG. 17, according to embodiments of the inventive concept,the semiconductor substrate 50 of FIG. 9 may be prepared. Thesemiconductor substrate 50 may include a second active region 64 in then-type impurity diffusion region 54 of FIG. 7. The semiconductorsubstrate 50 may have a third insulating layer 243 on the second activeregion 64. The third insulating layer 243 may include the first andsecond insulating layers 81 and 240 described with reference to FIGS. 8through 16. A connection hole 245 may be formed in the third insulatinglayer 243. The connection hole 245 may expose the second active region64. First and second barrier layers (not shown) may be sequentiallyformed on the third insulating layer 243 to conformally cover theconnection holes 245.

The first and second barrier layers may include the same material as thesecond buried pattern 116 and the third buried layer 120 of FIG. 10. Aninterconnection layer (not shown) may be formed on the second barrierlayer to fill the connection hole 245. The interconnection layer mayinclude the same material as the fifth buried layer 140 of FIG. 10.Third semiconductor photolithography and etching processes may beperformed on the first and second barrier layers and the interconnectionlayer. A photoresist pattern may be formed on the interconnection layerusing the third semiconductor photolithography process. The photoresistpattern may overlap the third interconnection structure 294 of thesecond active region 64 of FIG. 7.

By using the photoresist pattern and the third insulating layer 243 asan etch mask and an etch buffer layer, respectively, the first andsecond barrier layers and the interconnection layer may be etched usingthe third semiconductor etching process, thereby forming first andsecond barrier patterns 254 and 264 and an interconnection 274. Afterforming the first and second barrier patterns 254 and 264 and theinterconnection 274, the photoresist pattern may be removed from thesemiconductor substrate 50. As such, the first and second barrierpatterns 254 and 264 and the interconnection 274 may constitute thethird interconnection structure 294.

The third interconnection structure 294 may be included in a CMOStransistor 300 according to embodiments of the inventive concept. Theconnection hole 245 may be formed on each of first, third, and fourthactive regions 62, 66, and 68, the first interconnection structure 153,156, or 159, and the second interconnection structure 223, 226 or 229 asshown in FIG. 7. The connection hole 245 may be formed in the thirdinsulating layer 243 to expose each of the first, third, and fourthactive regions 62, 66, and 68, the first interconnection structure 153,156, or 159, and the second interconnection structure 223, 226, or 229.The third interconnection structure 294 may be formed in the connectionhole 245 of each of the first, third and fourth active regions 62, 66,or 68, the first interconnection structure 153, 156, or 159, and thesecond interconnection structure 223, 226, or 229.

In this case, the third interconnection structure 294 may be in contactwith a top surface of the first interconnection structure 153, 156, or159. The third interconnection structure 294 may be in contact with atop surface of the second interconnection structure 223, 226, or 229.The third interconnection structure 294 may apply an external powersource to each of the first through fourth active regions 62, 64, 66,and 68. The external power source of the third interconnection structure294 may be applied to each of the first interconnection structure 153,156, or 159 and the second interconnection structure 223, 226, or 229.

Embodiment 7

FIG. 18 is a schematic cross-sectional view taken along line III-III′ ofFIG. 7, illustrating a method of forming a CMOS transistor, according toembodiments of the inventive concept. In FIG. 18, the same referencenumerals are used to denote the same elements as in FIG. 17.

Referring to FIG. 18, according to embodiments of the inventive concept,a connection hole 245 may be formed in the semiconductor substrate 50and the third insulating layer 243 of FIG. 17. The connection hole 245may extend under a top surface of a second active region 64 through thethird insulating layer 243. The connection hole 245 may be formed ineach of first, third, and fourth active regions 62, 66 and 68, a firstinterconnection structure 153, 156, or 159, and a second interconnectionstructure 223, 226, or 229 as shown in FIG. 7.

The third interconnection structure 294 of FIG. 17 may be formed on thethird insulating layer 243 to fill the connection hole 245. The thirdinterconnection structure 294 of the second active region 64 may beincluded in a CMOS transistor 300 according to embodiments of theinventive concept. The third interconnection structure 294 may be formedin the connection hole 245 formed in each of the first, third, andfourth active regions 62, 66, and 68, the first interconnectionstructure 153, 156, or 159, and the second interconnection structure223, 226, or 229. In this case, the third interconnection structure 294may be partially inserted into the first interconnection structure 153,156, or 159 through a top surface of the first interconnection structure153, 156, or 159.

The third interconnection structure 294 may be partially inserted intothe second interconnection structure 223, 226, or 229 through a topsurface of the second interconnection structure 223, 226, or 229.

Embodiment 8

FIG. 19 is a schematic cross-sectional view taken along line III-III′ ofFIG. 7, illustrating a method of forming a CMOS transistor, according toembodiments of the inventive concept. In FIG. 19, the same referencenumerals are used to denote the same elements as in FIG. 17.

Referring to FIG. 19, according to embodiments of the inventive concept,a connection hole 245 may be formed on the semiconductor substrate 50 topenetrate the third insulating layer 243 of FIG. 17. The connection hole245 may expose a second active region 64. The first and second barrierlayers of FIG. 17 may be formed on the third insulating layer 243 toconformally cover the connection hole 245. A first interconnection layermay be formed on the second barrier layer to fill the connection hole245. The first interconnection layer may include the same material as ordifferent material from the interconnection layer of FIG. 17. Anetchback process and/or a CMP process may be performed on the first andsecond barrier layers and the first interconnection layer.

The first and second barrier layers and the first interconnection layermay be etched using the etchback process and/or the CMP process, therebyforming first and second barrier patterns 258 and 268 and a firstinterconnection 278 to fill the connection hole 245 and expose the thirdinsulating layer 243. A second interconnection layer (not shown) may beformed on the third insulating layer 243 to cover the first and secondbarrier patterns 258 and 268 and the first interconnection 278. Thesecond interconnection layer may include the same material as ordifferent material from the first interconnection 278. Fourthsemiconductor photolithography and etching processes may be performed onthe second interconnection layer.

A photoresist pattern may be formed on the second interconnection usingthe fourth semiconductor photolithography process. The photoresistpattern may overlap the third interconnection structure 298 of thesecond active region 64 of FIG. 7. By using the photoresist pattern andthe third insulating layer 243 as an etch mask and an etch buffer layer,respectively, the fourth semiconductor etching process may be performedon the second interconnection layer. The second interconnection layermay be etched using the fourth semiconductor etching process to exposethe third insulating layer 243, thereby forming the secondinterconnection 288.

The second interconnection 288 may constitute the third interconnectionstructure 298 along with the first and second barrier patterns 258 and268 and the first interconnection 278. The third interconnectionstructure 298 may be included in a CMOS transistor 300 according toembodiments of the inventive concept. The connection hole 245 may beformed on each of the first, third, and fourth active regions 62, 66,and 68, the first interconnection structure 153, 156, or 159, and thesecond interconnection structure 223, 226, or 229 as shown in FIG. 7.

The third interconnection structure 298 may be formed in the connectionhole 245 formed in each of the first, third, and fourth active regions62, 66 and 68, the first interconnection structure 153, 156, or 159, andthe second interconnection structure 223, 226, or 229. In this case, thethird interconnection structure 298 may be in contact with a top surfaceof the first interconnection structure 153, 156, or 159. The thirdinterconnection structure 298 may be in contact with a top surface ofthe second interconnection structure 223, 226, or 229.

Embodiment 9

FIG. 20 is a schematic cross-sectional view taken along line III-III′ ofFIG. 7, illustrating a method of forming a CMOS transistor, according toembodiments of the inventive concept. In FIG. 20, the same referencenumerals are used to denote the same elements as in FIG. 19.

Referring to FIG. 20, according to embodiments of the inventive concept,a connection hole 245 may be formed in the semiconductor substrate 50and the third insulating layer 243 of FIG. 19. The connection hole 245may extend under a top surface of a second active region 64 through thethird insulating layer 243. The connection hole 245 may be formed oneach of first, third, and fourth active regions 62, 66, and 68, firstinterconnection structure 153, 156, or 159, and second interconnectionstructure 223, 226, or 229 as shown in FIG. 7.

The third interconnection structure 298 of FIG. 19 may be formed on thethird insulating layer 243 to fill the connection hole 245. The thirdinterconnection structure 298 of the second active region 64 may beincluded in a CMOS transistor 300 according to embodiments of theinventive concept. The third interconnection structure 298 may be formedin each of the first, third, and fourth active regions 62, 66, and 68,the first interconnection structure 153, 156, or 159, and the secondinterconnection structure 223, 226, or 229.

In this case, the third interconnection structure 298 may be partiallyinserted into the first interconnection structure 153, 156, or 159through a top surface of the first interconnection structure 153, 156,or 159. The third interconnection structure 298 may be partiallyinserted into the second interconnection structure 223, 226, or 229through a top surface of the second interconnection structure 223, 226,or 229.

FIG. 21 is a schematic plan view of a semiconductor module including asemiconductor device of FIG. 7.

Referring to FIG. 21, a semiconductor module 330 according toembodiments of the inventive concept may include a module substrate 320.The module substrate 320 may be a printed circuit board (PCB), or aplate including an electrical circuit. The module substrate 320 mayinclude internal circuits (not shown), electrical pads (not shown), andconnectors 329. The internal circuits may be electrically connected tothe electrical pads and the connectors 329. Semiconductor packagestructures 315 and at least one resistor 323 may be disposed on themodule substrate 320.

Alternatively, the semiconductor package structures 315, the at leastone resistor 323, and at least one condenser 326 may be disposed on themodule substrate 320. The semiconductor package structures 315 may beelectrically connected to the electrical pads along with the at leastone resistor 323 and/or the at least one condenser 326. Each of thesemiconductor package structures 315 may include at least onesemiconductor device 310, which may include at least one CMOS transistor300 of FIG. 7.

The CMOS transistor 300 may include a p-type impurity diffusion region54 and an n-type impurity diffusion region 58. The p-type impuritydiffusion region 54 may include the first and second active regions 62and 64 of FIG. 7 in the semiconductor substrate 50 of FIG. 9. The firstactive region 62 may include the first interconnection structure 153,156, or 159 of FIG. 7. The selected third interconnection structures 294or 298 of FIG. 7 may be disposed on the first and second active regions62 and 64 and the first interconnection structure 153, 156, or 159.

The n-type impurity diffusion region 58 may include the third and fourthactive regions 66 and 68 of FIG. 7 in the semiconductor substrate 50 ofFIG. 9. The third active region 66 may include the secondinterconnection structure 223, 226, or 229 of FIG. 7. The remainingthird interconnection structures 294 or 298 may be disposed on the thirdand fourth active regions 66 and 68 and the second interconnectionstructure 223, 226, or 229. Thus, the semiconductor module 330 may havebetter electrical properties than in the conventional art.

The semiconductor module 330 may be electrically connected to theprocessor-based system 370 of FIG. 22 through the connectors 329 of themodule substrate 320.

FIG. 22 is a schematic plan view of a processor-based system including asemiconductor device of FIG. 7.

Referring to FIG. 22, a processor-based system 370 according toembodiments of the inventive concept may include at least one systemboard (not shown). The at least one system board may include at leastone bus line 365. A first module unit may be disposed on the at leastone bus line 365. The first module unit may be electrically connected tothe at least one bus line 365.

The first module unit may include a central processing unit (CPU) 343, afloppy disk drive (FDD) 346, and a compact disk read-only-memory (ROM)drive 349. Also, a second module unit may be disposed on the at leastone bus line 365. The second module unit may be electrically connectedto the at least one bus line 365.

The second module unit may include a first input/output (I/O) device352, a second I/O device 354, a ROM 356, and a random access memory(RAM) 358. The RAM 358 may include the semiconductor module 330 of FIG.21, according to embodiments of the inventive concept, or only thesemiconductor device 310 of FIG. 7. The ROM 356 may include thesemiconductor device 310 according to embodiments of the inventiveconcept. In this construction, the processor-based system 370 may havebetter electrical properties than in the conventional art.

The processor-based system 370 may include a computer system, a processcontrol system, or other systems.

As described above, embodiments of the inventive concept provide a CMOStransistor which includes a plurality of stacked diffusion stoppingmaterials disposed under work-function adjusting material. The diffusionstopping materials may prevent diffusion of constituent atoms of thepower applying material and protect insulating material thereunder. Thediffusion stopping materials may control a threshold voltage of the CMOStransistor to a desired value.

As a result, the CMOS transistor using the diffusion stopping materialsmay have better electrical properties than in the prior art. Also, theCMOS transistor may be disposed in a semiconductor device so that theelectrical properties of the semiconductor device can be improved overthose in the prior art. Furthermore, the semiconductor device may bedisposed in a semiconductor module and/or a processor-based system sothat the electrical properties of the semiconductor module and/or theprocessor-based system can be improved over those in the prior art.

The foregoing is illustrative of embodiments and is not to be construedas limiting thereof. Although a few embodiments have been described,those skilled in the art will readily appreciate that many modificationsare possible in embodiments without materially departing from the novelteachings and advantages. Accordingly, all such modifications areintended to be included within the scope of this inventive concept asdefined in the claims. In the claims, means-plus-function clauses areintended to cover the structures described herein as performing therecited function, and not only structural equivalents but alsoequivalent structures. Therefore, it is to be understood that theforegoing is illustrative of various embodiments and is not to beconstrued as limited to the specific embodiments disclosed, and thatmodifications to the disclosed embodiments, as well as otherembodiments, are intended to be included within the scope of theappended claims.

What is claimed is:
 1. A semiconductor device comprising: a substrateincluding a first region doped with a first conductivity type impurityand a second region doped with a second conductivity type impurity; afirst insulating layer disposed on the substrate and including a firsttrench in the first region and a second trench in the second region; afirst gate insulating layer disposed in the first trench; a first metalnitride layer disposed on the first gate insulating layer; a firstconcave-shaped metal containing layer disposed on the first metalnitride layer; a second concave-shaped metal containing layer disposedon the first concave-shaped metal containing layer; a first fillinglayer disposed on the second concave-shaped metal containing layer; afirst capping layer disposed on the first filling layer in the firsttrench and filling the first trench; a second gate insulating layerdisposed in the second trench; a second metal nitride layer disposed onthe second gate insulating layer; a third concave-shaped metalcontaining layer disposed on the second metal nitride layer; a secondfilling layer disposed on the third concave-shaped metal containinglayer; and a second capping layer disposed on the second filling layerin the second trench and filling the second trench, wherein a bottomsurface of the first filling layer is disposed higher than a bottomsurface of the second filling layer, the first capping layer includes amaterial having an etching rate different from that of the firstinsulating layer, and the second capping layer includes a materialhaving an etching rate different from that of the first insulatinglayer.
 2. The semiconductor device of claim 1, wherein the first regionincludes a p-type impurity diffusion region, and the second regionincludes an n-type impurity diffusion region.
 3. The semiconductordevice of claim 1, wherein the second concave-shaped metal containinglayer is not formed on an upper surface of a first sidewall of the firstconcave-shaped metal containing layer and not formed on an upper surfaceof a second sidewall of the first concave-shaped metal containing layer.4. The semiconductor device of claim 1, wherein the second filling layeris thicker than the first filling layer.
 5. The semiconductor device ofclaim 1, wherein the second filling layer is wider than the firstfilling layer.
 6. The semiconductor device of claim 1, furthercomprising a second insulating layer disposed on the first insulatinglayer.
 7. The semiconductor device of claim 1, wherein each of the firstgate insulating layer and the second gate insulating layer includes ahafnium-based material and/or a lanthanide-based material.
 8. Thesemiconductor device of claim 1, wherein each of the first metal nitridelayer and the second metal nitride layer is either binary-based metalnitride or ternary-based metal nitride.
 9. The semiconductor device ofclaim 1, wherein each of the first metal nitride layer and the secondmetal nitride layer includes HfN, TaN, TiN, WN, HfAlN, TaAlN or TiAlN.10. The semiconductor device of claim 1, wherein the firstconcave-shaped metal containing layer includes silicon nitride, siliconcarbide, or silicide of one selected from the group consisting ofhafnium (Hf), molybdenum (Mo), tantalum (Ta), titanium (Ti) and tungsten(W).
 11. The semiconductor device of claim 1, wherein the firstconcave-shaped metal containing layer includes HfAlN, HfSiN, TaAlN,TaSiN, TiAlN or TiSiN.
 12. The semiconductor device of claim 1, whereineach of the second concave-shaped metal containing layer and the thirdconcave-shaped metal containing layer includes carbide, nitride, siliconnitride or silicide of one selected from the group consisting of Hf, Mo,Ta, Ti and W, or includes platinum (Pt), ruthenium (Ru), iridium oxide(IrO) or ruthenium oxide (RuO).
 13. The semiconductor device of claim 1,wherein the second concave-shaped metal containing layer includes thesame material as the third concave-shaped metal containing layer, orincludes a different material from the third concave-shaped metalcontaining layer.
 14. A semiconductor device comprising: a substrateincluding a first region doped with a first conductivity type impurityand a second region doped with a second conductivity type impurity; aninsulating layer disposed on the substrate and including a first trenchin the first region and a second trench in the second region; a firstgate insulating layer disposed in the first trench; a first metalnitride layer disposed on the first gate insulating layer; a firstconcave-shaped metal containing layer disposed on the first metalnitride layer; a second concave-shaped metal containing layer disposedon the first concave-shaped metal containing layer; a first fillinglayer disposed on the second concave-shaped metal containing layer; afirst capping layer disposed on the first filling layer in the firsttrench and filling the first trench; a second gate insulating layerdisposed in the second trench; a second metal nitride layer disposed onthe second gate insulating layer; a third concave-shaped metalcontaining layer disposed on the second metal nitride layer; a secondfilling layer disposed on the third concave-shaped metal containinglayer; and a second capping layer disposed on the second filling layerin the second trench and filling the second trench, wherein a bottomsurface of the first filling layer is disposed higher than a bottomsurface of the second filling layer, and a top surface of the insulatinglayer is coplanar with a top surface of the first capping layer and witha top surface of the second capping layer.
 15. The semiconductor deviceof claim 14, wherein the first and second capping layer includes amaterial having an etching rate different from that of the insulatinglayer.
 16. The semiconductor device of claim 14, wherein a bottomsurface of the second concave-shaped metal containing layer is disposedhigher than a bottom surface of the third concave-shaped metalcontaining layer.
 17. The semiconductor device of claim 14, furthercomprising a second insulating layer disposed on the insulating layer.18. A semiconductor device comprising: a substrate; a first insulatinglayer disposed on the substrate and including a trench; a gateinsulating layer disposed in the trench; a metal nitride layer disposedon the gate insulating layer; a first concave-shaped metal containinglayer disposed on the metal nitride layer, and including a bottomportion, a first sidewall and a second sidewall; a second concave-shapedmetal containing layer disposed on the first concave-shaped metalcontaining layer; a filling layer disposed on the second concave-shapedmetal containing layer; and a capping layer disposed on the fillinglayer in the trench and filling the trench, wherein the secondconcave-shaped metal containing layer is not formed on an upper surfaceof the first sidewall of the first concave-shaped metal containing layerand not formed on an upper surface of the second sidewall of the firstconcave-shaped metal containing layer, and the capping layer includes amaterial having an etching rate different from that of the firstinsulating layer.
 19. The semiconductor device of claim 18, wherein thegate insulating layer is disposed on the substrate in the trench. 20.The semiconductor device of claim 18, wherein the second concave-shapedmetal containing layer includes a bottom layer, a first sidewall and asecond sidewall.
 21. The semiconductor device of claim 20, wherein thebottom layer of the second concave-shaped metal containing layer isdisposed on the bottom layer of the first concave-shaped metalcontaining layer, the first sidewall of the second concave-shaped metalcontaining layer are disposed on the first sidewall of the first secondconcave-shaped metal containing layer, and the second sidewall of thesecond concave-shaped metal containing layer are disposed on the secondsidewall of the first second concave-shaped metal containing layer. 22.The semiconductor device of claim 20, wherein the filling layer fills aspace defined by the bottom layer, the first sidewall and the secondsidewall of the second concave-shaped metal containing layer.
 23. Thesemiconductor device of claim 18, further comprising a second insulatinglayer disposed on the first insulating layer and on the capping layer.24. The semiconductor device of claim 18, wherein an upper surface ofthe filling layer is coplanar with an upper surface of the secondconcave-shaped metal containing layer.
 25. The semiconductor device ofclaim 18, wherein an upper surface of the capping layer is coplanar withan upper surface of the first insulating layer.
 26. The semiconductordevice of claim 18, wherein the first concave-shaped metal containinglayer includes HfAlN, HfSiN, TaAlN, TaSiN, TiAlN or TiSiN.
 27. Thesemiconductor device of claim 18, wherein the second concave-shapedmetal containing layer includes carbide, nitride, silicon nitride orsilicide of one selected from the group consisting of Hf, Mo, Ta, Ti andW, or includes platinum (Pt), ruthenium (Ru), iridium oxide (IrO) orruthenium oxide (RuO).
 28. A semiconductor device comprising: asubstrate; a first insulating layer disposed on the substrate andincluding a trench; a gate insulating layer disposed in the trench; ametal nitride layer disposed on the gate insulating layer; a firstconcave-shaped metal containing layer disposed on the metal nitridelayer, and including a bottom portion, a first sidewall and a secondsidewall; a second concave-shaped metal containing layer disposed on thefirst concave-shaped metal containing layer; a filling layer disposed onthe second concave-shaped metal containing layer; a capping layerdisposed on the filling layer in the trench and filling the trench; anda second insulating layer disposed on the first insulating layer,wherein the capping layer includes a material having an etching ratedifferent from that of the first insulating layer.
 29. The semiconductordevice of claim 28, wherein the second concave-shaped metal containinglayer is not formed on an upper surface of the first sidewall of thefirst concave-shaped metal containing layer and not formed on an uppersurface of the second sidewall of the first concave-shaped metalcontaining layer.
 30. The semiconductor device of claim 28, wherein anupper surface of the capping layer is coplanar with an upper surface ofthe first insulating layer.